Heretofore, such as shown in U.S. Pat. No. 3,823,911 dated July 16, 1974, a gate valve structure has been provided in which spacers have been positioned between opposed seat rings for an expanding gate assembly to maintain a predetermined minimum clearance between the seat rings so that "sticking" or binding of the gate assembly particularly at a closed position is minimized thereby to permit a relatively low operating torque for opening the gate and moving the gate between open and closed positions.
The spacers shown in Pat. No. 3,823,911 fit between opposed floating seats to limit the movement of the seats toward the gate assembly. The spacers are connected by pins to the seat skirts and a floating movement of the seat skirts and associated seat rings is permitted although a certain predetermined minimum spacing is maintained between the opposed seat rings by the spacers. However, the mounting of the spacers within the valve chamber to the seats is sometime difficult as the assembly is performed within a relatively small valve chamber and accurate alignment of the spacers is necessary in order to position the pins.